THE GM genie is out of the bottle but a small group of people in Pembrokeshire is doing its best to put back the stopper.

GM Free Cymru is an alliance of people from across the social spectrum whose initial campaign against plans to conduct a field trial of genetically modified maize next door to an organic farm has catapulted them to worldwide status as one of the leading GM watchdogs.

It took six weeks for the group to persuade the landowners of a farm at Mathry to call off the trials, but two years on they still have a catalogue of questions that no one seems able to answer.

Their careful researches have uncovered another interesting piece of information: that the first tests of a GM crop in Wales took place in Monmouthshire without anyone knowing.

Fields of GM oilseed rape were grown at White House Farm, Newcastle, near Monmouth, in 1997 and 1998.

As the plant can cross-pollinate weeds like the wild cabbage and wild turnip, the modified gene may already have spread unnoticed into the Welsh countryside.

But perhaps the most urgent fact the group has uncovered is that nobody is conducting tests on the possible effects of eating GM food.

It has hunted through scientific literature and asked the Government, the Royal Society and the Food Standards Authority for details of the papers they have used for their assertions that GM foods are safe.

"There has been a deafening silence," says former RAF officer Ian Panton, who has been handling scientific research on issues such as organophosphates and other pesticides and herbicides since 1995.

Then the group found papers relating to three tests. The United States Food and Drug Administration commissioned safety testing on GM tomatoes using rats. They suffered stomach lesions.

A second trial, which was fully peer reviewed and published, was carried out by Dr Arpad Pusztai who fed rats with a diet including GM potatoes.The animals suffered significant growth of the small bowel wall and some growth of the colonic wall. Abnormal growth is the first step towards a malignant cancer.

Finally Newcastle University carried out the only known feeding of GM food to humans under trial conditions. Those taking part were given a meal of a GM soya burger and a GM soya milk shake.

It was found that measurable amounts of the modified gene survived in the gut and transferred to gut bacteria. Other amounts were excreted, suggesting that the modified gene could enter the sewerage system and ultimately the wider environment and, critically, drinking water.

"We can't understand why there have not been more studies," said Chris Samra-Tibbetts, who acts as group co-ordinator. "We're not Luddites. We don't want to turn back the clock and we recognise that science has benefited the world enormously, but this has to be better tested.

"They keep saying there are all these studies that have been done, but none of us can get hold of them, and even Michael Meacher couldn't."

Former Environment Secretary Mr Meacher was sacked in the latest Cabinet reshuffle after expressing concern about GM food.

Gerald Miles, a Pembrokeshire family farmer who converted to organic production in 1997, believes the issue is crucial to agriculture.

"We are sitting on another time bomb like BSE and there is no need for it," he said.

Earlier this month the group issued a direct challenge to the Government in a letter to Prime Minister Tony Blair.

It reminded him of a pledge he made in an article he wrote for the Independent on Sunday in 2000 in which he said, "I can promise that no GM food will be put on the market here without going through the most rigorous safety assessments."

It asked Mr Blair to instigate clinical trials into eating GM food. It is still waiting for a reply.

Another group member, organic farmer Gill Rowlands said Mr Blair was urging people to support the biotech industry. "We agree with him, but this is dangerous.

"There have been no clinical trials and it's not been tested properly. The health position has not been researched.

"Why do we want to subject people to possible problems with their health?"